1. Field of the Invention
The present invention pertains to a mower assembly and particularly one employing an improved sickle guard to provide greater cutting action.
The standard sickle guard provides for a spacing between the sickle guard fingers which is equal to the spacing between the teeth of the sickle bar. Customarily, this is a 3-inch spacing. There is also a standard 3-inch stroke so that each tooth alternately moves betwen two sickle guard fingers. The movement of the single tooth against the sickle guard finger creates a shearing action. The sickle guard finger functions both to provide for the shearing action and also to support and protect the sickle blade as it moves back and forth.
The problem with the standard sickle guard is that a standard stroke equal to the spacing between the fingers slows down the machine and results in considerable shattering of the plants, resulting in substantial shatter loss. In other words, there is so much movement of the blades that the plants are hit sidewise, without cutting them, as the blade moves from one sickle guard finger to the next sickle guard finger.
2. Description of Prior Art
There have been various attempts to solve this problem. One of them involves placing twice as many sickle guard fingers on the sickle guard support. A typical sickle guard finger has a rearwardly facing slot through which the sickle bar moves. The problem with this is that the tight fit due to increased number of sickle guard fingers tends to result in binding problems in wet conditions. Furthermore, these extra fingers create more pushing problems in certain crops and large weeds. The additional finger sections are also very prone to breakage.
The Ronning U.S. Pat. No. 2,226,583 employs two fingers for each sickle guard section. One of these is a full sickle guard finger with a rearwardly facing slot, and the other one is a short finger which does engage the cutter blade in cutting engagement, but which does not support it by the use of a rearwardly facing slot, as is the case with the long fingers. While the arrangement of Ronning increases the number of cuts per stroke of the sickle and decreases the pushing problems that arise when twice as many long fingers are employed, the Ronning arrangement has certain drawbacks. In the first place, it is mounted on a vertically disposed flange. This is not a very satisfactory design for low height cutting as is required for a crop like soybeans. Furthermore, the individual teeth extend directly from the cross support bars and do not have any reinforcement. In additon, each tooth section is fastened by merely one fastener. This can result in the guard sections tilting slightly, causing alignment problems.
The Curtis U.S. Pat. No. 209,465 shows an arrangement in which there are a plurality of sections, each of which contains one long guard finger and one short one. It does use vertical bolts, unlike Ronning. On the other hand, there is only one bolt per section so that there would be a tendency for the sections to tip sidewise. Furthermore, in order to get four fingers, it is necessary to use two sections. There is no reinforcement for the guards and there would be a tendency for trash to collect between the various guard fingers.
The U.S. Patent to Kelley U.S. Pat. No. 1,581,214 shows an arrangement employing long and short fingers. There apparently is no contact with the knife with the short fingers. Also, there is only one long finger and one short finger for each guard section.